16621859 has 4 divisors (see below), whose sum is σ = 17158080. Its totient is φ = 16085640.

The previous prime is 16621853. The next prime is 16621877. The reversal of 16621859 is 95812661.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 16621859 - 2⁸ = 16621603 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16621853) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 268064 + ... + 268125.

It is an arithmetic number, because the mean of its divisors is an integer number (4289520).

Almost surely, 2^16621859 is an apocalyptic number.

16621859 is a deficient number, since it is larger than the sum of its proper divisors (536221).

16621859 is an equidigital number, since it uses as much as digits as its factorization.

16621859 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 536220.

The product of its digits is 25920, while the sum is 38.

The square root of 16621859 is about 4076.9914152473. The cubic root of 16621859 is about 255.2073617682.

The spelling of 16621859 in words is "sixteen million, six hundred twenty-one thousand, eight hundred fifty-nine".